16 HISTORICAL NOTES ON BEE DISEASES. 
mild and virulent foul brood is, that virulent foul brood is caused 
by a fungus which he named Cryptococcus alvearis, and that the mild 
foul brood is due to some other cause. His conclusion concerning 
the virulent foul brood was reached through a microscopic study of 
foul-brood material. Preuss had been somewhat familiar with bee- 
keeping since early boyhood, and had had the opportunity of visit- 
ing numerous apiaries in the Vistula Valley, but had not encountered 
foul brood until in 1866, when a friend had called his attention to the 
disease in an apiary of the latter in which he was using the Dzierzon 
hives. Preuss immediately undertook the investigation of the char- 
acter of the disease by studying microscopically the larve which had 
died of the disease. A small bit of the dead larve was added to a 
little water, covered with a glass, and studied in the fresh condition. 
Numerous spherical bodies measuring 2 » in diameter were seen and 
identified by him as belonging to the genus Cryptococcus, to which 
he gave the name Cryptococcus alvearis. Larger objects which were 
present were recognized as fat bodies. 
Very nearly related to this organism, Preuss writes, is a fungus 
that causes fermentation, Cryptococcus fermentum. It was his belief 
that if this latter species infected or fell upon a larva it might, under 
favorable temperature and moisture conditions, change into Crypto- 
coccus alvearis and in this way produce foul brood. Practical bee 
keepers had, prior to this time, emphasized the danger of foul brood 
transmission by the feeding of fermented honey. One bee keeper of 
large experience had attributed foul brood to meal feeding, and since 
meal is a good medium for the growth of fungi, Preuss was inclined 
to favor the view. He argued that since the fungus of fermentation 
is widespread in nature, the brood dying from cold or neglect of any 
kind may constitute a fruitful soil in which this fungus could grow 
and thus become the cause of infectious foul brood. Medication in 
the treatment of the disease Preuss held to be quackery and recom- 
mends instead the removal of the diseased frames from the hive, but 
not the destruction of the hives. The hives were to be washed with 
10 per cent sulphuric acid, followed by water, and afterwards put 
ito an oven and heated to the boiling temperature for some hours. 
The frames containing diseased material were to be burned, and 
those frames which were free from such material were to be used 
again. All dead bees were to be buried, as they might become a 
source of fungous growth, and the ground in front of the hive was to 
be sprinkled with sulphuric acid and then dug up deeply. 
SCHONFELD, NOVEMBER 15, 1873. 
In the absence of conclusive experimental proof, the theories 
advanced by Preuss in the paper just considered were not univer- 
